Individuals create a budget as a finance plan that describes how they will use their income. The budget can allocate income towards expenses, savings, and debt repayment. Generally a budget is created by looking at past spending and projecting that information and spending pattern into the future.
Some individuals fail to create a budget. Some individuals who create a budget fail to allocate their income according to the budget. Individuals spend more than they earn, driving themselves deeper into debt which can requires more of their income to be spent servicing the debt, which in turns leaves less income available.